1. Field of the Invention
The invention relates to a solid, non-inflatable recreational device, such as an inner tube, that provides the benefits of the prior art inflated devices without the maintenance.
2. Brief Description of the Prior Art
Inner tubes and other air filled devices have been used for recreational purposes for decades. One of the inherent problems associated with the standard inner tubes is the ease in which they puncture and tear. U.S. Pat. No. 4,936,804 recognizes the added durability of the closed cell foam, teaching the use of the material to make buoyancy aids. The buoyancy aids are small circular devices placed around the person's arms and legs to assist in maintaining the body afloat. Due to the size and limited buoyancy, the aids of the '804 patent are not difficult to construct, nor is weight an issue. As stated in the '804 patent, the aids "can be molded as an annular structure or formed from sheets of closed cell plastic foam cut into strips." While this manufacturing method is appropriate for the devices of the '804 patent, it is not applicable to actual flotation devices, such as inner tubes. Further, the small size of the '804 devices reduces the concern for overall weight of the devices, with other criteria, such as flexibility and floatability being the primary concern.
In U.S. Pat. No. 5,571,036 a linear tube of extruded foam is used as the buoyancy portion of floatation device. The '036 linear tube is designed to only support a user's head above water, as long as the user's head is placed within the "U" bend of the tube. In the '036 device, the doubled portion of the "U" bend is the only place along the length of the tube that has sufficient buoyancy.
The flotation device of the U.S. Pat. No. 5,628,658 also presents the problem of insufficient buoyant material to maintain a user's weight above water. The '658 is not, however, intended to maintain the user's body above water but rather assist in maintaining the user's head above water.
The linear tube of the '036 and '658 devices cannot merely be thickened and the ends secured to form a circular tube that has sufficient buoyancy to support a person. By the time there is sufficient material to support the weight of a person, the flexibility is minimized and the tube cannot be placed into a circular configuration. Further, since the overall amount of material used to manufacture the linear tubes is small enough, the overall weight is not of consequence. However, once sufficient material is used to form a circular tube able to support an average adult, the weight of the material of manufacture becomes a concern.
U.S. Pat. No. 5,295,884 recognizes the value in using plastics foam, however the design of the '884 devices does not address the construction problems encountered in manufacturing a circular tube of the configuration disclosed herein. The '884 device uses smaller rings placed around, and normal to, a larger ring. As noted in the '884 patent the rings abut together at the inner part of the annulus, while being separated at the outer periphery. This design avoids the problems associated with manufacturing circular tubes as well as eliminating the weight issues associated with solid objects having the mass required to support an average adult's body.
The disclosed device overcomes the weight and configuration problems associated with the prior art to produce a durable, lightweight device suitable for recreational use.